I have a friend who got hep C from blood during heart surgery in the 80’s.....try and get someone’s particular blood for a surgery - you cannot....they just put it into the “pool” for general use, and you get whatever comes to you.
If you know the surgery is coming, you can donate blood to yourself.
You can do specified donation for surgery. You get the blood that people you know have donated for your surgery. It does require your doctor filing a request with the Red Cross and your donors going to a specific location and telling them they are there to give for you.